Morrison tested as Labor leads in poll

Prime Minister Scott Morrison says he is not concerned about results of the latest poll which has the government still behind Labor on a two-party preferred basis.

The Fairfax-Ipsos poll gives Labor a 53-47 per cent two-party preferred lead over the coalition, down two points over the past month.

"We have been marked down from the events of several weeks ago and that is understandable," Mr Morrison told Channel 7 on Monday.

Mr Morrison took over the reins from Malcolm Turnbull last month after disunity within the Liberal party.

The Fairfax-Ipsos poll found only 49 per cent of voters believe the prime minister has the confidence of his party compared with 70 per cent for Mr Shorten.

However, there was some positive news for Mr Morrison.

The prime minister is considered trustworthy by 49 per cent of voters compared with 39 per cent for Mr Shorten.

And the former federal treasurer's economic credentials are rated by 66 per cent of voters, compared with 47 per cent for the opposition leader.

The government is expected to face pressure this week with Labor and the Greens seeking to refer Home Affairs Minister Peter Dutton to the High Court to test whether he is breaching the constitution over his family's financial interest in two childcare centres.

Mr Dutton says his legal advice puts his eligibility beyond doubt.

Labor leader Bill Shorten says the opposition will wait until it knows it has the support of some government MPs to try to refer Mr Dutton.

An inquiry report due on Wednesday will shed light on another matter affecting Mr Dutton - his ministerial decisions to approve visas for two au pairs.

Liberal unrest is expected to continue as party president Nick Greiner told ABC TV on Sunday night he didn't see why the results of the preselection in former prime minister Tony Abbott's seat of Warringah should not be publicly released.

The result of another preselection, in the seat of Wentworth vacated by Mr Turnbull, is also expected to be aired in parliament.

The Liberals preselected diplomat Dave Sharma, who does not live in the seat, despite Mr Morrison backing a female candidate.

Mr Sharma faces a tough test against independent candidate Dr Kerryn Phelps, who announced her nomination on Sunday.

Speaker Tony Smith will issue the writ for the October 20 by-election on Monday.

The government's credibility will also come under scrutiny on Tuesday with an inquiry into the controversial granting of $444 million to the Great Barrier Reef Foundation taking evidence from the foundation's management.

Labor will use parliament to seek details around the government's announcement of a royal commission into the aged-care system, which the coalition has previously rejected.

Mr Morrison's announcement on Sunday did not include the terms of reference, cost, timing or who will be the royal commissioners.